1. Field of the Invention
The present invention relates to an X-ray CT apparatus, and a medical image processing apparatus and a medical image processing method that generate and display information with time showing a result of blood flow perfusion analysis acquired from an object.
2. Description of the Related Art
Conventionally, a perfusion analysis of a blood flow in various organs of an object is performed using an image diagnostic apparatus such as an X-ray CT (computed tomography) apparatus, an MRI (magnetic resonance imaging) apparatus or a nuclear medicine diagnostic apparatus (see, for example, Japanese Publication of Patent Application No. 2006-247388). The conventional perfusion analysis is performed using data obtained with injecting a contrast medium or a tracer into an object. The perfusion analysis allows observing a dynamic state of a blood flow.
A color map is more often used as a display method of a result of the perfusion analysis. Observation that uses the color map is aggressively used in diagnosis of a blood flow dynamic state and a location of ischemia. Especially, the perfusion analysis in a vessel of a head or a tissue such as the heart or the liver sustained from vessels is a very significant analysis for understanding the function of the tissue.
FIG. 1 shows conventional graphs indicating TDCs (time density curves) of contrast medium obtained as a result of perfusion analysis. FIG. 2 is an image showing a method of displaying a perfusion analysis result obtained as the TDCs as shown in FIG. 1.
In each graph in FIG. 1, the ordinate axis denotes a CT value (HU: Hounsfield Unit) corresponding to a density of contrast medium injected into an object and the abscissa axis denotes time. The respective curves in FIG. 1 represent TDCs in respective ROIs (regions of interest) (ROI1, ROI2, ROI3, . . . ).
In the conventional perfusion analysis, a TDC of each ROI as shown in FIG. 1 is produced from pieces of X-ray CT data for plural ROIs obtained by injecting a contrast medium or a tracer. Then, perfusion parameters of the respective ROIs are calculated by various algorithms based on the produced TDCs.
The perfusion parameters obtained as a result of the perfusion analysis are separated by colors according to the data values and displayed as a color map as shown in FIG. 2.
However, the color map that is a conventional display method of a result of the perfusion analysis is to display a result including pieces of perfusion data at all time phases non-dynamically. That is, the color map displays a result of overlapping all pieces of the perfusion data obtained from an object in the time axis direction.
Therefore, there is a problem that it becomes difficult to understand a blood flow dynamic state intuitively since information in the perfusion data such as how from which direction blood flow flows cannot be observed over time.